I know this isn't specifically Audio Visual equipment, but it's kind of related and guitar forums are unlikely to be much help here, so hoping you can 
I have just purchased a Casio MG-510.
The way these guitars work, is they have a Hexaphonic pickup which is the same as a normal humbucking guitar pickup but has 12 low-impedance coils (about 0.5Kohm) rather than 2, which essentially detects all of the strings individually. Each signal is then fed through an individual analogue processing circuit and then into a digital signal processing circuit which then feeds it out the MIDI port and into your chosen synthesizer/computer soundcard.
These guitars are nearly 40 years old now and rare as heck... There is nothing quite like them out there, as these use the general Midi output rather than the proprietary nonsense Roland and other manufacturers use. Most are also starting to fail, with the same issue, which is that the electrolytic capacitors leak or die.
Mine mostly works which is brilliant, but the B string is totally dead. No sound or reaction at all. I believe i've narrowed it down to the analogue processing board, as I would expect all strings to be impacted if the DSP board had failed.
I ran my multimeter set to Ohms across all of the caps on the analogue board. All of them show a reading, except for one which shows infinite resistance.... I go down the schematic and sure enough, it's an electrolytic cap in the circuit for the B string... So I think replacing it will fix it. However, I also figured that I would just buy a whole new batch of caps and perhaps do the whole lot and future proof it.
I'm going through Mouser adding caps to my basket. I wanted Panasonic, as they are the originals but I've ended up mostly with Nichicon or Wurth.
Most don't call out the ESR but this one does:
33 uF and has a ESR of 2.33 Ohms.... is that high ? Is that something to be concerned by? The fact none of the others have called it out, is kind of confusing?
On the analogue board, I believe the caps are for a Band-Pass Filter and then Gain Controller.
Do I need to think more logically about this approach, i.e. should I be looking for equivalent part numbers rather than just general replacements? One thing I noted from the parts list, most of these caps have been out of manufacture for well over 20 years, so finding equivalents would be tricky. I have all of the specifications though.
Thanks
I have just purchased a Casio MG-510.
The way these guitars work, is they have a Hexaphonic pickup which is the same as a normal humbucking guitar pickup but has 12 low-impedance coils (about 0.5Kohm) rather than 2, which essentially detects all of the strings individually. Each signal is then fed through an individual analogue processing circuit and then into a digital signal processing circuit which then feeds it out the MIDI port and into your chosen synthesizer/computer soundcard.
These guitars are nearly 40 years old now and rare as heck... There is nothing quite like them out there, as these use the general Midi output rather than the proprietary nonsense Roland and other manufacturers use. Most are also starting to fail, with the same issue, which is that the electrolytic capacitors leak or die.
Mine mostly works which is brilliant, but the B string is totally dead. No sound or reaction at all. I believe i've narrowed it down to the analogue processing board, as I would expect all strings to be impacted if the DSP board had failed.
I ran my multimeter set to Ohms across all of the caps on the analogue board. All of them show a reading, except for one which shows infinite resistance.... I go down the schematic and sure enough, it's an electrolytic cap in the circuit for the B string... So I think replacing it will fix it. However, I also figured that I would just buy a whole new batch of caps and perhaps do the whole lot and future proof it.
I'm going through Mouser adding caps to my basket. I wanted Panasonic, as they are the originals but I've ended up mostly with Nichicon or Wurth.
Most don't call out the ESR but this one does:
33 uF and has a ESR of 2.33 Ohms.... is that high ? Is that something to be concerned by? The fact none of the others have called it out, is kind of confusing?
On the analogue board, I believe the caps are for a Band-Pass Filter and then Gain Controller.
Do I need to think more logically about this approach, i.e. should I be looking for equivalent part numbers rather than just general replacements? One thing I noted from the parts list, most of these caps have been out of manufacture for well over 20 years, so finding equivalents would be tricky. I have all of the specifications though.
Thanks
